Propulsion unit for airplanes



April 6, 1965 B. EcKERT PROPULSION UNIT FOR AIRPLANES Filed July 28. 1961 INVENTOR BRUNO ECK ERT iii A TTORNE YS.

vwith diiculties and in a very uneconomical form.

United States Patent O The present invention relates to a combination propulr Asion or drive unit for propelling airplanes, essentially consisting of a ram jet unit and of a gas turbine jet propulsion unit, preferably built concentrically into the ram jet propulsion unit, which together or alternately take over the propulsion of the airplane, namely the gas turbine jet propulsion unit during starting and in the relatively low velocity range and the ram jet propulsion unit yin the relatively high velocity range whereby with a turnedoff turbine drive unit the air inlet thereof is blocked or closed off.

As already mentioned, the combination propulsion or drive units are provided for airplanes which are intended to cover a very large velocity range up to a velocity of Mach 5. The drive unit installations presently available to date for airplanes are, individually considered, either `not capable to cover the entire velocity range or the characteristics thereof do not permit at all an operation in one of the two velocity ranges. In that connection, it should be mentioned that the gas turbine jet drive or propulsion unit can be used, for velocities above 2.5 to 3 Mach, only In contrast thereto, the ram jet drive or propulsion unit is particularly suitable for these relatively high velocities and above such velocities whereas the ram jet drive unit is not capable to start of its own force or to develop with low velocities a sufficient output.

For the foregoing reasons, recourse is had to the socalled combined or combination drive or propulsion units which are composed of a gas turbine jet drive unit and of a ram jet drive unit. It is thereby appropriate and necessary in the flight Mach range above 3 in which the gas turbine jet drive unit is rendered inoperative for purposes of avoiding thermal overloads as a result of the arcodynamic heaing effect due to the ram effect, to avoid a flow or passage of the air through the gas turbine jet drive unit. Since at flight velocities of Mach number 5 the pressure ratio as a result of the aerodynamic ram effector Velocity head with internal or rectilinear impact `diffusors is of the order of magnitude of approximately `3() and with external or inclined impact difusors of approximately 150 and consequently temperature increases occur of the order of magnitude between 600 and 900 C., the simple closure mechanisms such as iris diaphragms or sheet metal flaps which have been used heretofore or yhave been proposed to date for the closing of gas turbine jet drive units no longer measure up to the intended task by reason of the heat damages occurring therein.

The present invention is concerned with the task to yproduce a closure for the air inlet of the gas turbine jet 3,176,462 Patented Apr. 6, 1965 ice in accordance with the present invention for closing the air inlet of the gas turbine jet drive unit to provide an aerodynamically correct closure body in front of the gas turbine jet drive unit which is arranged centrally thereof and substantially concentrically therewith and which is adapted to be displaced in the longitudinal direction of the drive unit. Y

According to a further development of the present invention, it is additionally proposed to construct the closure body member of double-conical shape land to provide the same with a guide part which is displaceably supported within the compressor drive shaft whereby, in the closure position thereof, the compressor inlet is closed olf by the rear conical portion of the closure body member.

With a supersonic air inlet constructed as an inclined impact dilusor, it is additionally proposed in accordance with the present invention to arrange the closure body member within the central body member of the inclined impact difusor. One embodiment in accordance with the present invention may thereby consist of an arrangement in which the forward conical portion of the closure body member forms the apex or peak of the inclined impact diffuser or of the central body member, the forward aperture of which serves, with a retracted closure body member, as air inlet for the gas turbine drive unit.

During simultaneous operation of the two drive units, namely of the gas turbine jet drive unit and of the ram jet drive unit, the closure body member is in the retracted position thereof in which it frees the forward air inlet aperture of the central body member. The rear part of the closure body member thereby forms the inner wall of the rear section of the air inlet for the gas turbine jet drive unit.

There is produced by an arrangement according to the present invention a heat resistant and therewith operationally safe closure of the air inlet for the gas turbine jet drive unit. The closure body member thereby simultaneously assumes also certain functions of the air inlet. In the last-mentioned modification of the present invention, this is the case both during operation of the ram jet drive unit as also during operation of the gas turbine jet drive unit.

Accordingly, it is an object of the present invention to provide a combination propulsion installation for propelling aircrafts adapted to cover a very wide range of flight velocities and consisting of a ram jet drive unit and of a gas turbine drive unit which effectively eliminates,

.in a simple manner, the shortcomings and inadequacies of the prior art constructions.

It is another object of the present invention to provide a combination propulsion unit for aircrafts essentially consisting of a ram jet drive unit and of a gas turbine drive unit which is reliable and safe in operation even at flight velocities, for example, at Mach 5 in which there occurs substantial heating of certain'inarts of the unit.

Still another object of the present invention resides in the provision of a combination propulsion or drive unit for aircrafts consisting of a ram jet drive unit and of a gas turbine jet drive unit in which a flow of air through the gas turbine jet drive unit is eifectively prevented within the flight velocity range in whichl the gas turbine jet drive unit is rendered inoperative without producing excessive heating of the parts eifectuating closure of the air inlet.

Still a further object of the invention resides in the provision of a closure member for gas turbine jet drive units particularly those associated with, and preferably disthat of FIGUREI. Y I v.

Referring now to the drawing and more particularly .Y

posed within a ramjjet unit, whichis capable ofwithstanding the thermal stresses to which such closure rnemf ber'may be subjected at. speeds in excess of 2.5 or4" 3 Mach. f Y e, Y Still another object of the Vpresent invention resides in the provision of closure' means for the airinlet of agas accordance with thepre'sent inventionfit( is understood Y,that the. same .is`,not. limited thereto but is susceptible of `manychanges and :modifications within thespirit and scopethereof, and Iy therefore do not Wish tobe limited turbinejet drive unit for `aircrafts, particularly for a gas'.

turbine unit arranged concentrically within a ram`. jet, which are not only capable of withstanding the maximum thermal loads and stresses but also take over other operational functions 'invarious` operatingV phases of the Ypro- K pulsion unit.

These and other objects, features andadvantages of the present-invention willbecome more obvious rfrom the n following description whentalrenin connection with the accompanying, drawing which'shows, for-purposes ofv illustration only, two embodiment'sin accordance with the `V present invention and wherein f FIGURE 1 is a somewhat schematic longitudinal cross l sectional 'view through a first embodimentrof `a combina- .tiondriveunit,and y f FIGURE 2 is a somewhat schematic longitudinal cross sectional view through a modified embodiment of acom- -bination 'propulsion' unit inaccordance with the present member is differenty from.

invention in which the closure to' FIGUREyl'; the combinedY drive unitillustrated therein is compcysedfof` a ram jet drive unit generally designated by reference character S andof a gas turbinejet drive unit generally designated by vreference charactery G, the Vgas .to the details shown and described herein but intend to cover such changes yand modications as are encompassed bythe scope of the appended claims.

I claim: Y Y Y 1.* A combination propulsion vunit for airplanes comprising ram jet propulsionl means and gas turbine jet'pro- Y pulsion means which'together'oralternately provide the i X repulsion vmeansfor the plane, .namely said gas turbine jet propulsion means during startingvand in .the Vrelatively low velocity rangeand said ra-m jet propulsion means in the relatively high velocityrange, said ram jet' fpropul sion "means includinga'ram jet pipe-having' asupersonic air -inlet,'. supersonic Vditfusor means arranged` adjacent .said yair inlet, a 'combustion chamber, fuel injcction'means Y `andthrust nozzle means` said gasrturbine jet propulsion means being arranged within said ram jet propulsion means coaxially'thereof, said gas turbine jet propulsion [means including' a housing'containing aturbo-compressor i havingla drive fshaft,"`a"combustion chamber, fuel injecftionvmeans, a gas turbiney anda thrust nozzlemeans, said vhousing being provided with Vairinlet means forthe compressor, closure means for the air inlet means of said gas turbine propulsion means adaptedto -beclosedv when the 'Y gas turbine Vpfrcipulsion means is renderedA inoperative,

turbine'jetdrive'unit-G being-arranged concentricallywith in the rarnjet drivev unit'S, The gaslturbineldrive unit4 `G comprises, as its'rnain parts, a turbo-compressor'u,

a combustion chamber 12 providedwithconventional inf jeetionmeans, a gas turbine.13,` an air. inlet 14 and-'a Yfront of said air inlet meansfor said gas turbine propul;

V-said supersonic diffusori-means being'constructed asin- 'clinedf impact diffuser having al central body member,

said c'cntralrbody; member beingl .disposed in said supersonic ,airinlet, 'said closure means being arranged .in

sion means and including an aerodynam-icallyj correct closure bodyv member having aforward conical portionv and a rear "conical portion, and' means for displacing.

said ,closure body member in the longitudinal direction of said gasturbinepropulsion means to a rearward cio-L A sure position 'and a forward position to ythereby selectively Apulsion means with the rear conical portion of said lclosure'body membe'rclojsingsaid air inlet means for the vigas turbine propulsion means`r vin -said rearward closure tion means and'the thrust nozzle 24r all of which again may beV of conventional construction."

The guide. part AV30 of .an*aerodynamically*correct clog sure body member generally designated by reference numeral v31 is supported longitudinally displaceably within the compressor drivevshaft 16.itse'lf of ,hollow construction. The closure bodymember 31/which itself, isfaccommodated within the central body member r21is constructed of double concial shape wherebythe.. rear coni-f cal portion 31 closes, in the retracted position of the closure member 31indicatedin FIGURE 1v in dash line, the air inlet '14' for vthecomp'ressor 11 of the gas turbine 'jetdriveunitG/- l In the Vembodimentof FIGURE IZy in which elements corresponding to those` of` .FIGURE 1 are designated by similar reference numerals 'of the 100 series, the for# ward conicalportionf131f of the closure bo'dy member. generally'designatedV by reference numeral 131 forms,v in v :ope-n and close said Ainletmeans''forthegas turbine proposition of saidclosure means, and said forwardconical portion beingY receivedl in said central body member inY said forward positionofsaid closure body member.`

' 2, A vcombination propulsion unit for airplanesV com- ,-prising ram .jet propulsion means and gasturbine jetpropulsion Vmeans which'together or alternatively provide the propulsion meansfor the plane;` namely said gas turfbine jet propulsion means duringstarting and in the relal"tivelylovv velocity range and said ramjetrpropulsion theforward postion thereof, the .point or apex of the central Ibody member lzlrprovided with an airinlet aper- 'ture 114 for Athe compressor 111. Inthe forward 'posi tion of the closure body member r13.1, the `air inletfor' the compressorflll ofthe gaslturbine'r jet'drive unit G'A is effectively'closed-fori.Y 'In contrast thereto, in the ref tracted position of the closure body member 131, thefair inlet 11'4 for'the gas Aturbine jetdrive unit fG is freedV or openedupxwherebythe rear.; conical portion 131 of the` closure'body member, 1'31 ,forms theinnen WallA of the rear1sectionof the air inlet and cooperates, -n this task, with: appropriately shaped 'bine unitV housing.v l f ,f

While Ihave shown and described two embodiments in inner wall portions Vof theatur- *Y f rnea-ns'in therelativelyhigh velocity range, said ram jet propulsionmeans including a ram jet pipe-havingY a ysupersonic airr inlet, Ysupersonic diffuser means .arranged adjacent said. air inlet, a combustion chamber, fuel injection means and thrust nozzle means,4 said gasturbine jet `propulsion Vmeans Abeing` arranged within said ram jet propulsionv means coaxially thereof, said gas turbine' jet propulsion'means including 'a housing containing aturbo.-`

compressor-having a drive shaft," a combustion chamber,

Vgfuelinjection means, fa gas turbine land l-a` thrust nozzle Vmea-ns, 'said,housing'-being '1:rovided with air'inlenmeans v for the compressor, closure means lfor the air inlet means VAof .saidgas turbinejet propulsion means adapted to be -closed when the` gas..t1'1rbine propulsion means is rendered inoperative, said supersonic difusor means being Vconstructed as inclined impact diiusor' having a vcentral Ybody lmember,sai`dr central body member beinghollow ,and being .disposed within said supersonic air inlet, said` `closure means being larranged jin front` of said air inlet meansV for said Vgas. turbine propulsion means .and including an aerodynamically correct'closure body member and -a guide member thereforV arranged so as to be longitudinallydisplaceable within said compressor drive shaft,

, 6 y said closure body member having a forward conical pormember in the forward position of said closure body rtion and a rear conical portion, means for displacing said member which coiTesponds to the operative condition elo-sure body member in the longitudinal direction of said of said gas turbine jet drive means.

gas turbine propulsion means to thereby selectively open and close said inlet means for the gas turbine propulsion 5 References Cited in the l 0f this patent means With the rear conical portion of said closure body UNITED STATES PATENTS member closing said air inlet means for the gas turbine propulsion means in the closure position of `said closure gowns --OMYl means, and the forward conical portion of said closure 2970431 Hlssrlnn; Fb 7 1961 body member being received Within said central body 10 

1. A COMBINATION PROPULSION UNIT FOR AIRPLANES COMPRISING RAM JET PROPULSION MEANS AND GAS TURBINE JET PROPULSION MEANS WHICH TOGETHER OR ALTERNATELY PROVIDE THE PROPULSION MEANS FOR THE PLANE, NAMELY SAID GAS TURBINE JET PROPULSION MEANS DURING STARTING AND IN THE RELATIVELY LOW VELOCITY RANGE AND SAID RAM JET PROPULSION MEANS IN THE RELATIVELY HIGH VELOCITY RANGE, SAID RAM JET PROPULSION MEANS INCLUDING A RAM JET PIPE HAVING A SUPERSONIC AIR INLET, SUPERSONIC DIFFUSOR MEANS ARRANGED ADJACENT SAID AIR INLET, A COMBUSTION CHAMBER, FUEL INJECTION MEANS AND THRUST NOZZLE MEANS, SAID GAS TURBINE JET PROPULSION MEANS BEING ARRANGED WITHIN SAID RAM JET PROPULSION MEANS COAXIALLY THEREOF, SAID GAS TURBINE JET PROPULSION MEANS INCLUDING A HOUSING CONTAINING A TURBO-COMPRESSOR HAVING A DRIVE SHAFT, A COMBUSTION CHAMBER, FUEL INJECTION MEANS, A GAS TURBINE AND A THRUST NOZZLE MEANS, SAID HOUSING BEING PROVIDED WITH AIR INLET MEANS FOR THE CONPRESSOR, CLOSURE MEANS FOR THE AIR INLET MEANS OF SAID GAS TURBINE PROPULSION MEANS ADAPTED TO BE CLOSED WHEN THE GAS TURBINE PROPULSION MEANS IS RENDERED INOPERATIVE, SAID SUPERSONIC DIFFUSOR MEANS BEING CONSTRUCTED AS INCLINED IMPACT DIFFUSOR HAVING A CENTRAL BODY MEMBER, SAID CENTRAL BODY MEMBER BEING DISPOSED IN SAID SUPERSONIC AIR INLET, SAID CLOSURE MEANS BEING ARRANGED IN FRONT OF SAID AIR INLET MEANS FOR SAID GAS TURBINE PROPULSION MEANS AND INCLUDING AN AERODYNAMICALLY CORRECT CLOSURE BODY MEMBER HAVING A FORWARD CONICAL PORTION AND A REAR CONICAL PORTION, AND MEANS FOR DISPLACING SAID CLOSURE BODY MEMBER IN THE LONGITUDINAL DIRECTION OF SAID GAS TURBINE PROPULSION MEANS TO A REARWARD CLOSURE POSITION AND A FORWARD POSITION TO THEREBY SELECTIVELY OPEN AND CLOSE SAID INLET MEANS FOR THE GAS TURBINE PROPULSION MEANS WITH THE REAR CONICAL PORTION OF SAID CLOSURE BODY MEMBER CLOSING SAID AIR INLET MEANS FOR THE GAS TURBINE PROPULSION MEANS IN SAID REARWARD CLOSURE POSITION OF SAID CLOSURE MEANS, AND SAID FORWARD CONICAL PORTION BEING RECEIVED IN SAID CENTRAL BODY MEMBER IN SAID FORWARD POSITION OF SAID CLOSURE BODY MEMBER. 